There is a growing need for investigators who are trained in biomedical computing and related fields as they directly relate to application domains, including health care delivery, basic biomedical research, clinical and translational research and public health. Based on our experience with our existing Informatics Training Program over the past 4 years, we are now proposing to continue and expand this training program. The educational philosophy that undergirds this Program is that (1) there is a core body of knowledge that is shared by multiple domains of profession-based informatics; (2) specialized training is also needed in these professions; (3) this training requires didactic and practical exposure; (4) many unanswered questions remain in each domain; 5) research is needed in each domain and (5) trainees' learning experience is enhanced by contact with fellows and faculty from a wide variety of backgrounds. The proposed program comprises a core program for all specialties, with optional public health and health librarianship tracks. The program common to all trainees consists of the following: Mentored research, five required courses (Health Sciences Informatics Applications; Health Sciences Informatics Data, Information, Knowledge; Health Sciences Informatics Evaluation; Decision Support and Knowledge-based Systems; and Health Sciences Informatics Security, Confidentiality, and Privacy), up to two enabling courses (generally in databases and networking), courses in human subjects research (Research Methods; Research Ethics); offerings to foster an informatics identity (Orientation, Fellows Seminar, Research in Progress); a variety of elective course; and required practica and mentored research. The Public Health Track includes three additional courses: Informatics in Public Health, Data Standards in Public Health, and Public Health and the National Health Information Network. Mentoring for research is available from faculty throughout the health sciences campus and the University as a whole. Practica are available throughout the Baltimore-Washington area in academic, public, and private sector locations. The current program confers a Masters of Science in Health Sciences Informatics. The Public Health Track includes the courses: Informatics in Public Health, Data Standards in Public Health, and Public Health and the National Health Information Network. The Health Librarianship Track includes mentoring by librarians from the Welch Medical Library. We are pursuing a joint DrPH/MS in informatics as part of our ongoing interests in public health informatics. Individual opportunities exist for pursuing interests in bioinformatics and clinical-research informatics.